DAQ VXI-SC-1000 User manual

VXI-SC-1000

VXI-SC-1102 User Manual
32-Channel Multiplexer Amplifier Module
February 1997 Edition
Part Number 321385A-01
© Copyright 1997 National Instruments Corporation. All Rights Reserved.

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Important Information
Warranty
The VXI-SC-1102 is warranted against defects in materials and workmanship for a period of one year from the date
of shipment, as evidenced by receipts or other documentation. National Instruments will, at its option, repair or replace
equipment that proves to be defective during the warranty period. This warranty includes parts and labor.
The media on which you receive National Instruments software are warranted not to fail to execute programming
instructions, due to defects in materials and workmanship, for a period of 90 days from date of shipment, as evidenced
by receipts or other documentation. National Instruments will, at its option, repair or replace software media that do
not execute programming instructions if National Instruments receives notice of such defects during the warranty
period. National Instruments does not warrant that the operation of the software shall be uninterrupted or error free.
A Return Material Authorization (RMA) number must be obtained from the factory and clearly marked on the outside
of the package before any equipment will be accepted for warranty work. National Instruments will pay the shipping
costs of returning to the owner parts which are covered by warranty.
National Instruments believes that the information in this manual is accurate. The document has been carefully
reviewed for technical accuracy. In the event that technical or typographical errors exist, National Instruments reserves
the right to make changes to subsequent editions of this document without prior notice to holders of this edition. The
reader should consult National Instruments if errors are suspected. In no event shall National Instruments be liable for
any damages arising out of or related to this document or the information contained in it.
EXCEPT AS SPECIFIED HEREIN, NATIONAL INSTRUMENTS MAKES NO WARRANTIES, EXPRESS OR IMPLIED, AND
SPECIFICALLY DISCLAIMS ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR APARTICULAR PURPOSE.
CUSTOMER’SRIGHT TO RECOVER DAMAGES CAUSED BY FAULT OR NEGLIGENCE ON THE PART OF NATIONAL
INSTRUMENTS SHALL BE LIMITED TO THE AMOUNT THERETOFORE PAID BY THE CUSTOMER. NATIONAL INSTRUMENTS
WILL NOT BE LIABLE FOR DAMAGES RESULTING FROM LOSS OF DATA, PROFITS, USE OF PRODUCTS, OR INCIDENTAL OR
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Instruments will apply regardless of the form of action, whether in contract or tort, including negligence. Any action
against National Instruments must be brought within one year after the cause of action accrues. National Instruments
shall not be liable for any delay in performance due to causes beyond its reasonable control. The warranty provided
herein does not cover damages, defects, malfunctions, or service failures caused by owner’s failure to follow the
National Instruments installation, operation, or maintenance instructions; owner’s modification of the product;
owner’s abuse, misuse, or negligent acts; and power failure or surges, fire, flood, accident, actions of third parties, or
other events outside reasonable control.
Copyright
Under the copyright laws, this publication may not be reproduced or transmitted in any form, electronic or mechanical,
including photocopying, recording, storing in an information retrieval system, or translating, in whole or in part,
without the prior written consent of National Instruments Corporation.
Trademarks
LabVIEW®, NI-DAQ®, RTSI®, ComponentWorks™, CVI™, Measure™, SCXI™, and VirtualBench™ are
trademarks of National Instruments Corporation.
Product and company names listed are trademarks or trade names of their respective companies.
WARNING REGARDING MEDICAL AND CLINICAL USE OF NATIONAL INSTRUMENTS PRODUCTS
National Instruments products are not designed with components and testing intended to ensure a level of reliability
suitable for use in treatment and diagnosis of humans. Applications of National Instruments products involving
medical or clinical treatment can create a potential for accidental injury caused by product failure, or by errors on the
part of the user or application designer. Any use or application of National Instruments products for or involving
medical or clinical treatment must be performed by properly trained and qualified medical personnel, and all traditional
medical safeguards, equipment, and procedures that are appropriate in the particular situation to prevent serious injury
or death should always continue to be used when National Instruments products are being used. National Instruments
products are NOT intended to be a substitute for any form of established process, procedure, or equipment used to
monitor or safeguard human health and safety in medical or clinical treatment.

© National Instruments Corporation v VXI-SC-1102 User Manual
Table
of
Contents
About This Manual
Organization of This Manual........................................................................................ix
Conventions Used in This Manual................................................................................x
National Instruments Documentation ........................................................................... xi
Customer Communication ............................................................................................xi
Chapter 1
Introduction
About the VXI-SC-1102............................................................................................... 1-2
What You Need to Get Started .....................................................................................1-3
Software Programming Choices ................................................................................... 1-3
National Instruments Application Software ...................................................1-3
NI-DAQ Driver Software ............................................................................... 1-4
VXIplug&play Instrument Driver .................................................................. 1-5
Optional Equipment...................................................................................................... 1-6
Unpacking.....................................................................................................................1-6
Chapter 2
Installation
Current-Loop Receivers................................................................................................ 2-3
Installing Your Hardware ............................................................................................. 2-4
Chapter 3
Signal Connections
Front Connector ............................................................................................................3-1
Signal Descriptions ......................................................................................... 3-3
Channel Input Signal Connections .................................................................3-3
Ground-Referencing Your Signals................................................... 3-4
Cold-Junction Sensor Connection .................................................................. 3-6

Table of Contents
VXI-SC-1102 User Manual vi © National Instruments Corporation
Chapter 4
Theory of Operation
Functional Overview .................................................................................................... 4-1
VXIbus Interface .......................................................................................................... 4-2
Digital Control Circuitry .............................................................................................. 4-2
Analog Circuitry........................................................................................................... 4-3
Analog Input Channels................................................................................... 4-3
Analog Output................................................................................................ 4-3
Chapter 5
Calibration
Calibration Equipment Requirements .......................................................................... 5-1
Gain and Offset Calibration.......................................................................................... 5-2
Sample Program for Calibration................................................................................... 5-4
Appendix A
Specifications
Appendix B
Customer Communication
Glossary
Index
Figures
Figure 1-1. VXI Signal Conditioning System.......................................................... 1-1
Figure 1-2. The Relationship between the Programming Environment, Your
Instrument Driver, and Your VXI-DAQ Hardware .............................. 1-5
Figure 2-1. VXI-SC-1102 Parts Locator Diagram................................................... 2-2
Figure 2-2. Bent and Trimmed Resistor................................................................... 2-3
Figure 3-1. VXI-SC-1102 Front Connector Pin Assignments ................................. 3-2
Figure 3-2. Ground-Referenced Signal Connection................................................. 3-5
Figure 3-3. Floating Signal Connection Referenced to Chassis Ground ................. 3-6

Table of Contents
© National Instruments Corporation vii VXI-SC-1102 User Manual
Figure 4-1. VXI-SC-1102 Block Diagram ...............................................................4-1
Figure 5-1. Analog Bus Receptacle Pin Assignment ............................................... 5-2
Tables
Table 3-1. Front Connector Signal Descriptions..................................................... 3-3

© National Instruments Corporation ix VXI-SC-1102 User Manual
About
This
Manual
This manual describes the electrical and mechanical aspects of the
VXI-SC-1102 and contains information concerning its installation and
operation. The VXI-SC-1102 is a signal conditioning submodule in the
VXI-data acquisition (VXI-DAQ) line of National Instruments
products. The VXI-SC-1102 is designed for signal conditioning of
thermocouples, volt and millivolt sources, and 4 to 20 mA sources or
0 to 20 mA process-current sources. The VXI-SC-1102 has 32
differential analog input channels and one cold-junction sensor channel.
Organization of This Manual
The VXI-SC-1102 User Manual is organized as follows:
• Chapter 1, Introduction, describes the VXI-SC-1102, lists what
you need to get started, optional software and optional equipment,
and explains how to unpack the VXI-SC-1102.
• Chapter 2, Installation, describes how to install current-loop
receivers on your VXI-SC-1102 and gives information about
installing your VXI-SC-1102 submodule into the VXI-SC-1000
carrier module.
• Chapter 3, Signal Connections, describes the input signal
connections to the VXI-SC-1102 submodule via the front
connector.
• Chapter 4, Theory of Operation, contains a functional overview of
the VXI-SC-1102 and explains the operation of each functional
unit.
• Chapter 5, Calibration, discusses the calibration procedures for the
VXI-SC-1102.
• Appendix A, Specifications, lists the specifications for the
VXI-SC-1102.
• Appendix B, Customer Communication, contains forms you can
use to request help from National Instruments or to comment on our
products.

About This Manual
VXI-SC-1102 User Manual x
© National Instruments Corporation
•TheGlossary contains an alphabetical list and description of terms
used in this manual, including abbreviations, acronyms, metric
prefixes, mnemonics, symbols, and general data acquisition terms.
•TheIndex contains an alphabetical list of key terms and topics in
this manual, including the page where you can find each one.
Conventions Used in This Manual
The following conventions are used in this manual.
< > Angle brackets containing numbers separated by an ellipsis represent a
range of values associated with a port, bit, or signal name (for example,
ACH<0..7> stands for the signals ACH0 through ACH7).
bold italic Bold italic text denotes a note, caution, or warning.
italic Italic text denotes emphasis, a cross reference, or an introduction to a
key concept.
monospace Denotes text or characters that are to be literally input from the
keyboard, sections of code, programming examples, and syntax
examples. This font is also used for the proper names of disk drives,
paths, directories, programs, subprograms, subroutines, device names,
functions, variables, filenames, and extensions, and for statements and
comments taken from program code.
PC Refers to the IBM PC/XT, the IBM PC AT, and compatible computers.
VXI-MIO module Refers to any of the National Instruments VXI-MIO Series of plug-in
data acquisition boards.
carrier module Refers to the VXI-SC-1000, which plugs directly into a VXI slot and on
which VXI-SC submodules are installed.
VXI-SC submodule Refers to VXI signal conditioning hardware that installs onto the carrier
module.
Abbreviations, acronyms, metric prefixes, mnemonics, symbols, and
terms are listed in the Glossary.

About This Manual
© National Instruments Corporation xi VXI-SC-1102 User Manual
National Instruments Documentation
The VXI-SC-1102 User Manual is one piece of the documentation set
for your VXI-DAQ system. You could have any of several types of
documents, depending on the hardware and software in your system.
Use the different types of documents you have as follows:
• Your VXI-DAQ hardware user manuals—These manuals have
detailed information about the VXI-DAQ hardware that plugs into
or is connected to your VXIbus chassis. Use these manuals for
hardware installation and configuration instructions, specification
information about your VXI-DAQ hardware, and application hints.
• Software documentation—You may have both application software
and driver software documentation. National Instruments
application software includes ComponentWorks, LabVIEW,
LabWindows®/CVI, Measure, and VirtualBench. National
Instruments driver software includes NI-DAQ and VXIplug&play
instrument drivers. After you set up your hardware system, use
either your application or driver software documentation to help
you write your application. If you have a large, complicated
system, it is worthwhile to look through the software
documentation before you configure your hardware.
• Accessory installation guides or manuals—If you are using
accessory products, read the terminal block and cable assembly
installation guides or accessory board user manuals. They explain
how to physically connect the relevant pieces of the system.
Consult these guides when you are making your connections.
Customer Communication
National Instruments wants to receive your comments on our products
and manuals. We are interested in the applications you develop with our
products, and we want to help if you have problems with them. To make
it easy for you to contact us, this manual contains comment and
configuration forms for you to complete. These forms are in
Appendix B, Customer Communication, at the end of this manual.

© National Instruments Corporation 1-13 VXI-SC-1102 User Manual
Chapter
1
Introduction
This chapter describes the VXI-SC-1102, lists what you need to get
started, optional software and optional equipment, and explains how to
unpack the VXI-SC-1102.
The VXI-SC-1102 is part of the VXI signal conditioning system, which
consists of a carrier module and one or more VXI signal conditioning
submodules or filler panels as shown in Figure 1-1.
Figure 1-1. VXI Signal Conditioning System
1 Analog Bus Receptacle
2SCMPs
3 SCMP Socket
4 Address Switch
5 VXI-SC Subslot 1
6 VXI-SC Subslot 2
7 VXI-SC Carrier Module
8 VXI-SC-1150 Submodule
9 VXI-SC Submodule
1
2
5
6
9
7
8
3
4
To VXIbus
Chassis

Chapter 1 Introduction
VXI-SC-1102 User Manual 1-14
© National Instruments Corporation
The VXI-SC-1000 is a carrier module that installs into a slot in a
VXIbus chassis and is populated with one or two submodules. The
VXI-SC-1102 is a submodule that installs into VXI-SC subslots on a
VXI-SC-1000 carrier module.
Your VXI-SC-1000 carrier module is shipped with a filler panel
installed in one of the submodule sites. This filler panel is necessary for
the attachment of the front panel, so you should leave it in place until
you are ready to install a VXI-SC submodule.
About the VXI-SC-1102
The VXI-SC-1102 is a submodule for the signal conditioning of
thermocouples, low-bandwidth volt and millivolt sources, 4 to 20 mA
current sources, and 0 to 20 mA process-current sources. The
VXI-SC-1102 has 32 differential analog input channels and one
cold-junction sensor channel. On each channel, the VXI-SC-1102 has a
three-pole lowpass filter with a 2 Hz cutoff frequency to reject 60 Hz
noise. Each channel also has an amplifier with a selectable gain of 1 or
100. You can multiplex the VXI-SC-1102 inputs to a single output,
which drives a single VXI-MIO board channel.
The VXI-SC-1102 operates with full functionality with National
Instruments VXI-MIO modules. You can multiplex several
VXI-SC-1102 submodules and other VXI signal conditioning
submodules into a single channel on the VXI-MIO module, greatly
increasing the number of analog input signals that you can digitize.
You can also use National Instruments terminal blocks, which have
screw terminals to which you attach the input signals for the
VXI-SC-1102. In addition, some of these terminal blocks have a
temperature sensor for thermocouple cold-junction compensation
(CJC). The VXI-SC-1102 multiplexes this cold-junction sensor with the
32 input channels during a hardware scan. A National Instruments
isothermal terminal block is recommended for thermocouple
applications.
Detailed specifications of the VXI-SC-1102 are listed in Appendix A,
Specifications.

Chapter 1 Introduction
© National Instruments Corporation 1-15 VXI-SC-1102 User Manual
What You Need to Get Started
To set up and use your VXI-SC-1102, you will need the following
items:
❑VXI-SC-1102 submodule
❑VXI-SC-1102 User Manual
❑VXI-SC-1000 carrier module and documentation
❑VXI-MIO module and documentation
❑One of the following software packages and documentation:
ComponentWorks
LabVIEW for Windows
LabWindows/CVI for Windows
NI-DAQ for PC compatibles
VirtualBench
VXIplug&play instrument driver
❑Your VXIbus system
Software Programming Choices
There are several options to choose from when programming your
National Instruments VXI-DAQ hardware. You can use LabVIEW,
LabWindows/CVI, ComponentWorks, VirtualBench, or other
application development environments with either NI-DAQ or the
VXIplug&play instrument driver. Both NI-DAQ and the
VXIplug&play instrument driver access the VXI-DAQ hardware
through the VISA driver software.
National Instruments Application Software
LabVIEW features interactive graphics, a state-of-the-art user
interface, and a powerful graphical programming language. The
LabVIEW Data Acquisition VI Library, a series of VIs for using
LabVIEW with National Instruments DAQ hardware, is included with
LabVIEW. The LabVIEW Data Acquisition VI Library is functionally
equivalent to the NI-DAQ software.

Chapter 1 Introduction
VXI-SC-1102 User Manual 1-16
© National Instruments Corporation
LabWindows/CVI features interactive graphics, a state-of-the-art user
interface, and uses the ANSI standard C programming language. The
LabWindows/CVI Data Acquisition Library, a series of functions for
using LabWindows/CVI with National Instruments DAQ hardware, is
included with the NI-DAQ software kit. The LabWindows/CVI Data
Acquisition Library is functionally equivalent to the NI-DAQ software.
ComponentWorks contains tools for data acquisition and instrument
control built on NI-DAQ driver software. ComponentWorks provides a
higher-level programming interface for building virtual instruments
through standard OLE controls and DLLs. With ComponentWorks, you
can use all of the configuration tools, resource management utilities,
and interactive control utilities included with NI-DAQ.
VirtualBench features VIs that combine DAQ products, software, and
your computer to create a standalone instrument with the added benefit
of the processing, display, and storage capabilities of your computer.
VirtualBench instruments load and save waveform data to disk in the
same forms that can be used in popular spreadsheet programs and word
processors.
Using LabVIEW, LabWindows/CVI, ComponentWorks, or
VirtualBench software will greatly reduce the development time for
your data acquisition and control application.
NI-DAQ Driver Software
The NI-DAQ driver software is included at no charge with all National
Instruments DAQ hardware. NI-DAQ is not packaged with accessory
products. NI-DAQ has an extensive library of functions that you can
call from your application programming environment. These functions
include routines for analog input (A/D conversion), buffered data
acquisition (high-speed A/D conversion), analog output (D/A
conversion), waveform generation, digital I/O, counter/timer
operations, SCXI, RTSI, self-calibration, messaging, and acquiring
data to extended memory.
NI-DAQ has both high-level DAQ I/O functions for maximum ease of
use and low-level DAQ I/O functions for maximum flexibility and
performance. Examples of high-level functions are streaming data to
disk or acquiring a certain number of data points. An example of a
low-level function is writing directly to registers on the DAQ device.
NI-DAQ does not sacrifice the performance of National Instruments

Chapter 1 Introduction
© National Instruments Corporation 1-17 VXI-SC-1102 User Manual
DAQ devices because it lets multiple devices operate at their peak
performance.
NI-DAQ maintains a consistent software interface among its different
versions so that you can change platforms with minimal modifications
to your code.
VXI
plug&play Instrument Driver
National Instruments distributes VXIplug&play instrument drivers free
of charge. VXIplug&play instrument drivers are one level above the
NI-DAQ device driver and contain high-level software functions whose
architecture is specified by the VXIplug&play Systems Alliance. The
VXIplug&play standards increase interoperability with other vendors,
and ensure that drivers are designed and presented in a consistent
fashion that facilitates ease of use. Refer to Figure 1-2 to see the
relationship between your software components.
Figure 1-2. The Relationship between the Programming Environment, Your
Instrument Driver, and Your VXI-DAQ Hardware
ComponentWorks,
LabVIEW, LabWindows/CVI,
or VirtualBench
VXI
plug&play
Instrument Driver
NI-DAQ Driver Software
VISA
VXI-DAQ Hardware
Other Application
Development Environments

Chapter 1 Introduction
VXI-SC-1102 User Manual 1-18
© National Instruments Corporation
Optional Equipment
National Instruments offers a variety of products to use with your
VXI-SC-1102 module, as follows:
• Terminal blocks and 96-pin cables that allow you to attach input
signals to your submodule
• SCXI Process Current Resistor Kit
For more specific information about these products, refer to your
National Instruments catalogue or call the office nearest you.
Unpacking
Your VXI-SC-1102 submodule is shipped in an antistatic package to
prevent electrostatic damage to the submodule. Electrostatic discharge
can damage several components on the submodule. To avoid such
damage in handling the submodule, take the following precautions.
• Ground yourself via a grounding strap or by holding a grounded
object.
• Touch the antistatic package to a metal part of your VXIbus chassis
before removing the submodule from the package.
• Remove the submodule from the package and inspect the
submodule for loose components or any other sign of damage.
Notify National Instruments if the module appears damaged in any
way. Do not install a damaged submodule into your VXIbus
chassis.
•Never touch the exposed pins of connectors.

© National Instruments Corporation 2-19 VXI-SC-1102 User Manual
Chapter
2
Installation
This chapter describes how to install current-loop receivers on your
VXI-SC-1102 and gives information about installing your
VXI-SC-1102 submodule into the VXI-SC-1000 carrier module.
Refer to Figure 2-1, VXI-SC-1102 Parts Locator Diagram, for
information as you read the instructions in this chapter.

Chapter 2 Installation
VXI-SC-1102 User Manual 2-20
© National Instruments Corporation
1 Serial Number 2 Product Name 3 Assembly Number 4RCL x Pads
3
4
2
1

Chapter 2 Installation
© National Instruments Corporation 2-21 VXI-SC-1102 User Manual
Figure 2-1. VXI-SC-1102 Parts Locator Diagram
Current-Loop Receivers
The VXI-SC-1102 has pads for transforming individual channels to
current-to-voltage converters. National Instruments offers an SCXI
Process Current Resistor Kit of four 249 Ω, 0.1%, 5 ppm, 1/4 W
resistors. The reference designators for the current loop resistors have
the following format: for input channel x, the resistor is RCLx. For
example, the resistor for channel 28 is RCL28.
Warning: Before installing the resistors in your submodule, make sure that there are
no signals connected to your submodule front connector.
Install the resistors by performing the following steps:
1. Follow the instructions in the VXI-SC-1000 Carrier Module
Installation Guide to remove the VXI-SC-1102 submodule from
the carrier assembly.
2. Bend and trim the resistor lead as shown in Figure 2-2. Be sure that
the resistor does not extend more than 0.65 in. above the surface of
the circuit board.
Figure 2-2. Bent and Trimmed Resistor
3. Insert the resistor into the appropriate pad, labeled RCLx.
4. Solder the leads to the pad on the bottom side of the module.
5. Follow the instructions in the VXI-SC-1000 Carrier Module
Installation Guide to replace the VXI-SC-1102 submodule in the
carrier assembly.

Chapter 2 Installation
VXI-SC-1102 User Manual 2-22
© National Instruments Corporation
Installing Your Hardware
Follow the instructions in the VXI-SC-1000 Carrier Module Installation
Guide to replace the VXI-SC-1102 submodule and to install the
assembled VXI-SC carrier module in the VXIbus chassis.